RESUMO
AIM: To evaluate the microtensile bond strength of self-etching adhesive systems in dentin treated with 2% chlorhexidine digluconate (CHX). MATERIALS AND METHODS: The occlusal surfaces of 20 human molars were removed and divided into eight groups: 1A, Clearfil SE adhesive (SE) with self-etching technique (TS); 1B, SE with TS and previous application of CHX; 2A, Scotchbond Universal (SBU) adhesive with TS; 2B, SBU adhesive with TS and previous application of CHX; 1C, SE with total-etching technique (TT); 1D, SE with TT and previous application of CHX; 2C, SBU with TT; 2D SBU with TT and previous application of CHX. Composite resin (5mm) was applied on the hybridized surface. Samples were subjected to microtensile test and evaluated on Scanning Electron Microscope (SEM) and with energy-dispersive X-ray (EDX). RESULTS: Low values of bond strength were observed in groups 1A (39,77±11,56) and 2A (40,84±12,49) comparing with 1B (22,86±5,18) and 2B (27,02±5,58). TS group presented adhesive type remover fracture while TT groups presented cohesive at the top of hybrid layer. EDX revealed the presence of CHX crystals for TS, which was not found in the TT. CONCLUSION: The previous application of chlorhexidine on dentin decreased the bond strength of adhesive systems on self-etching technique.
Assuntos
Clorexidina , Colagem Dentária , Humanos , Clorexidina/química , Cimentos Dentários , Colagem Dentária/métodos , Cimentos de Resina/química , Resinas Compostas/química , Dentina , Resistência à Tração , Adesivos Dentinários/química , Teste de Materiais , AdesivosRESUMO
The objective of this study was to determine whether the hardness of etch-and-rinse adhesives may be affected by the pretreatment of acid-etched dentin with potassium oxalate desensitizer. Unerupted human third molars were cut into crown segments by removing the occlusal enamel and roots. The pulp chamber of these crown segments was connected to a syringe barrel filled with phosphate-buffered saline so that the moisture of dentin was maintained during the bonding procedures. Three etch-and-rinse adhesives-two two-step systems (Adper Single Bond 2 [SB], One-Step [OS]) and one three-step system (Adper Scotchbond Multi-Purpose [MP])-were applied to acid-etched dentin that had been treated (experimental groups) or not (control groups) with potassium oxalate (BisBlock). The Knoop hardness (KHN) of adhesives was taken at different sites of the outer surface of the adhesive-bonded dentin. The KHN of the three tested adhesives applied to acid-etched dentin treated with potassium oxalate was significantly lower than that exhibited by the respective controls (not treated with oxalate; p<0.05). Regardless of the adhesive, the treatment with potassium oxalate reduced the adhesives' KHN (p<0.05), with the OS system exhibiting the lowest KHN compared with the MP and SB systems.
Assuntos
Dessensibilizantes Dentinários/química , Adesivos Dentinários/química , Oxalatos/química , Condicionamento Ácido do Dente/métodos , Cimentos Dentários/química , Dureza , Humanos , Cura Luminosa de Adesivos Dentários , Teste de Materiais , Metacrilatos/química , Ácido Oxálico/química , Ácidos Fosfóricos/química , Polimerização , Cimentos de Resina/química , Propriedades de SuperfícieRESUMO
The aim of this study was to determine whether using a silane-containing universal adhesive as a silane primer in glass-ceramic/resin cement systems affects biaxial flexural strength (BFS) and bonded interface integrity after loading. Glass-ceramic (IPS e.max CAD, Ivoclar/Vivadent, Schaan, Liechtenstein) disc-shaped specimens (6.5±0.1mm in diameter, 0.5±0.1mm thick) were etched with 5% hydrofluoric acid (HF) for 20 seconds and divided into four groups of 30 specimens, to be treated as follows: 1) One bottle silane primer (RCP); 2) Separate application of silane and adhesive (RCP+SB); 3) Silane-containing universal adhesive (SBU); 4) No treatment (C). After silanization, all specimens were resin cement- coated and polymerized for 40 seconds. Each specimen layer was measured, as well as each assembly's thickness, using a digital caliper and scanning electron microscope (SEM). Specimens were stored for 24 hours and submitted to a BFS test (1.27 mm/min). BFS values were calculated using the bilayer disc-specimen solution. Bonded interfaces were analyzed on fractured fragments using SEM. One-way ANOVA and Tukey tests (α=0.05) were applied, as well as the Weibull analysis. Factor "silane treatment" was statistically significant ( p<0.0001). RCP+SB (372.2±29.4 MPa) and RCP (364.2±29.5 MPa) produced significantly higher BFS than did the C (320.7±36.3 MPa) or SBU (338.0±27.1 MPa) groups. No differences were found in the Weibull modulus ( m: RCP: 10.1-17.3; RCP+SB: 10.1-17.0; SBU: 12.3-22.4; C: 7.4-12.9). Bonded interface analysis exhibited ceramic-cement separation (SBU, C) and voids within the resin cement layer (all groups). Neither the ceramic/cement system's BFS nor its bonded interface stability were improved by SBU after loading.
Assuntos
Colagem Dentária , Cimentos de Resina , Condicionamento Ácido do Dente , Cerâmica , Cimentos Dentários , Porcelana Dentária , Análise do Estresse Dentário , Resistência à Flexão , Teste de Materiais , Silanos , Propriedades de SuperfícieRESUMO
Host-derived proteases have been reported to degrade the collagen matrix of incompletely-resin-infiltrated dentin. This study tested the hypothesis that interfacial degradation of resin-dentin bonds may be prevented or delayed by the application of chlorhexidine (CHX), a matrix metalloproteinase inhibitor, to dentin after phosphoric acid-etching. Contralateral pairs of resin-bonded Class I restorations in non-carious third molars were kept under intra-oral function for 14 months. Preservation of resin-dentin bonds was assessed by microtensile bond strength tests and TEM examination. In vivo bond strength remained stable in the CHX-treated specimens, while bond strength decreased significantly in control teeth. Resin-infiltrated dentin in CHX-treated specimens exhibited normal structural integrity of the collagen network. Conversely, progressive disintegration of the fibrillar network was identified in control specimens. Auto-degradation of collagen matrices can occur in resin-infiltrated dentin, but may be prevented by the application of a synthetic protease inhibitor, such as chlorhexidine.
Assuntos
Bis-Fenol A-Glicidil Metacrilato/química , Clorexidina/química , Colagem Dentária , Adesivos Dentinários/química , Dentina/ultraestrutura , Inibidores de Metaloproteinases de Matriz , Inibidores de Proteases/química , Condicionamento Ácido do Dente/métodos , Resinas Compostas/química , Restauração Dentária Permanente , Colágenos Fibrilares/ultraestrutura , Humanos , Teste de Materiais , Microscopia Eletrônica de Transmissão , Ácidos Fosfóricos/química , Estresse Mecânico , Propriedades de Superfície , Resistência à Tração , Fatores de TempoRESUMO
Loss of hybrid layer integrity compromises resin-dentin bond stability. Matrix metalloproteinases (MMPs) may be partially responsible for hybrid layer degradation. Since chlorhexidine inhibits MMPs, we hypothesized that chlorhexidine would decelerate the loss of resin-dentin bonds. Class I preparations in extracted third molars were sectioned into two halves. One half was customarily restored (etch-and-rinse adhesive/resin composite), and the other was treated with 2% chlorhexidine after being acid-etched before restoration. Specimens were stored in artificial saliva with/without protease inhibitors. Microtensile bond strengths and failure mode distribution under SEM were analyzed immediately after specimens' preparation and 6 months later. With chlorhexidine, significantly better preservation of bond strength was observed after 6 months; protease inhibitors in the storage medium had no effect. Failure analysis showed significantly less failure in the hybrid layer with chlorhexidine, compared with controls after 6 months. In conclusion, this in vitro study suggests that chlorhexidine might be useful for the preservation of dentin bond strength.
Assuntos
Anti-Infecciosos Locais/química , Clorexidina/química , Colagem Dentária , Adesivos Dentinários/química , Dentina/ultraestrutura , Condicionamento Ácido do Dente , Resinas Compostas/química , Preparo da Cavidade Dentária/classificação , Restauração Dentária Permanente/métodos , Humanos , Microscopia Eletrônica de Varredura , Inibidores de Proteases/química , Saliva Artificial/química , Estresse Mecânico , Propriedades de Superfície , Resistência à Tração , Fatores de TempoRESUMO
This study aimed to evaluate the effect of various silane-containing solutions on bonding between resin cement and glass ceramic after 24 hours and after six months of water storage. Glass-ceramic plaques (IPS e.max CAD) were sandblasted with aluminum oxide, etched with 10% hydrofluoric acid (HF), and divided into five "silane treatment" groups: RelyX Ceramic Primer (RCP), RelyX Ceramic Primer and Single Bond Plus (RCP+SB), Scotchbond Universal (SBU), Clearfil Ceramic Primer (CP), and no solution (HF-only control). Each group was divided into two "storage time" subgroups: 24 hours or six months in 37°C water. Eighteen resin cement cylinders (RelyX Ultimate) were bonded to each treatment group substrate (n=18) and then subjected to microshear testing. Failure mode was analyzed using scanning electron microscopy. Debond data were analyzed using a two-way analysis of variance and the Tukey post hoc test (α=0.05) as well as Weibull distributions. The factors "silane treatment," "storage time," (p<0.0001), and their interaction were statistically significant (p<0.0010). Group means (MPa±SD), RCP (24 hours: 27.2±3.1; six months: 18.0±4.9), and HF-only control (24 hours: 21.1±3.4; six months: 15.7±5.8) showed a reduced bond strength after six months of water storage, while RCP + SB (24 hours: 23.4±4.4; six months: 22.2±5.4), SBU (24 hours: 18.8±3.0; six months: 17.2±3.6), and CP (24 hours: 21.7±4.3; six months: 17.4±4.8) remained constant. Weibull analysis revealed that more reliable bond strengths were obtained after six months for SBU and RCP + SB. Evaluation by scanning electron microscopy revealed that all groups demonstrated hydrolytic degradation at six months of storage, but RCP + SB and SBU indicated less. Use of a separate application of silane and adhesive system improved short and long-term ceramic/resin cement bond strength.
Assuntos
Cerâmica/uso terapêutico , Colagem Dentária/métodos , Cimentos Dentários/uso terapêutico , Cimentos de Resina/uso terapêutico , Bis-Fenol A-Glicidil Metacrilato/uso terapêutico , Análise do Estresse Dentário , Humanos , Metacrilatos/uso terapêutico , Polietilenoglicóis/uso terapêutico , Ácidos Polimetacrílicos/uso terapêutico , Silanos/uso terapêuticoRESUMO
Temperature affects the polymerization behavior of dimethacrylate-based materials. This study describes the influence of pre-polymerization temperature and exposure duration on polymerization kinetics of a commercial dental photo-activated composite at the top and at 2-mm depth. We used the temperature-controlled stage of a diamond-attenuated-total-reflectance unit to pre-set composite temperature between 3 degrees and 60 degrees C. Composite was light-exposed by a conventional quartz-tungsten-halogen curing unit for 5, 10, 20, or 40 sec. Real-time conversion, maximum conversion rate (R(p)(max)), time to achieve R(p)(max), and conversion at R(p)(max) were calculated from infrared spectra. Composite pre-warming enhanced maximal polymerization rate and overall monomer conversion (top significantly greater than 2 mm). Time when R(p)(max) occurred did not change with temperature, but occurred sooner at the top than at 2-mm depth. Conversion at R(p)(max) increased with temperature, allowing more of the reaction to occur prior to vitrification than at room temperature.
Assuntos
Resinas Compostas/química , Materiais Dentários/química , Resinas Compostas/efeitos da radiação , Materiais Dentários/efeitos da radiação , Temperatura Alta , Humanos , Cinética , Luz , Iluminação/instrumentação , Teste de Materiais , Polímeros/química , Espectrofotometria Infravermelho , Propriedades de Superfície , Temperatura , Fatores de TempoRESUMO
The potential for maximizing conversion of room-temperature, photoactivated resin composite in the oral environment is limited. Pre-heating composite prior to light-curing is hypothesized to increase monomer conversion and reduce the duration of light exposure. Composite temperature was controlled at between 3 degrees C and 60 degrees C prior to exposure with a conventional quartz-tungsten-halogen curing unit: 5, 10, 20, or 40 sec. Monomer conversion was calculated from infrared spectra at 0 mm (top) and 2-mm-deep surfaces 5 min after light initiation. A strong, positive correlation existed between temperature and monomer conversion: top r(2) = 0.999, 2 mm r(2) = 0.998. Conversion ranged from 31.6% (3 degrees C) to 67.3% (60 degrees C). The duration of light exposure, reduced by 50 to 75% with pre-heated composite, yielded the same or significantly higher conversion (p = 0.001) than with control (22 degrees C, 20 sec). Both hypotheses were accepted: Pre-heating composite prior to photoactivation provides greater conversion requiring reduced light exposure than with room-temperature composite.
Assuntos
Resinas Compostas/química , Temperatura Alta , Cimentos de Resina/química , Análise de Variância , Dureza , Teste de Materiais , Polímeros/química , Estatísticas não ParamétricasRESUMO
OBJECTIVE: The purpose of this study was to measure the tensile bond strength (TBS) testing of resin composite to dentin of three low-viscosity composites, in association with an unfilled adhesive, and a filled adhesive one and two coats respectively, and to evaluate and compare the SEM morphological observations. METHODS: The labial surface of 120 bovine lower incisors were ground to obtain a flat dentin surface allowing demarcation of a 4 mm diameter area with adhesive tape. The teeth were randomly divided in six groups of 20 each. The dentin of each ground surface was etched with 35% H(3)PO(4) for 15s, followed by application of the respective adhesive: Single Bond (SB) for Groups 1, 2, 3 and 6; Optibond Solo (OS) for Groups 4 and 5. In Groups 1 and 4, a resin composite rod with a wire loop was luted directly to the adhesive surface with Z100. Group 2 received an intermediate layer of Flow It (FI) composite; Group 3 received an intermediate layer of Protect Liner F (PLF) composite; Group 5 received a second coat of OS; and Group 6 received an intermediate layer of an experimental low-viscosity composite (EM). A resin composite rod was luted to the surface of each specimen with Z100 resin composite. All specimens were stored in distilled water at 37 degrees C for 24h prior to TBS testing. Each specimen was inspected by SEM and classified according to adhesive or cohesive failure mode. One specimen of each group was cut longitudinally, polished and prepared for SEM observation. RESULTS: The TBS values were: Group 1 (7.86MPa+/-2.28), Group 2 (7.62MPa+/-1.85), Group 3 (7.60MPa+/-2.14), Group 4 (7.96MPa+/-2.36), Group 5 (7.50MPa+/-2.70) and Group 6 (7.18MPa+/-2.40). No significant statistical differences were observed among the groups. However, the analyses of the failure mode presented a considerable variation. SIGNIFICANCE: The use of a filled adhesive or an unfilled adhesive along with a low-viscosity composite as an intermediate layer may provide a stress absorbing layer, whereby improving the preservation of the bonded interface area.
Assuntos
Resinas Compostas , Colagem Dentária/métodos , Falha de Restauração Dentária , Adesivos Dentinários , Cimentos de Resina , Adesivos , Análise de Variância , Animais , Bis-Fenol A-Glicidil Metacrilato , Bovinos , Adaptação Marginal Dentária , Permeabilidade da Dentina , Elasticidade , Teste de Materiais , Metacrilatos , Microscopia Eletrônica de Varredura , Dióxido de Silício , Propriedades de Superfície , Resistência à Tração , Viscosidade , ZircônioRESUMO
PURPOSE: The aim of this study was to evaluate the shear bond strength of two adhesive systems when applied on dentin surfaces with different degrees of wetness. MATERIALS AND METHODS: Two-hundred ten dentin specimens were used. After conditioning with 35% phosphoric acid gel and washing, seven methods of drying dentin were used: 30 s air spray (groups 1 and 2), 5 s air spray (groups 3 and 4), dry cotton pellets (groups 7 and 8), wet cotton pellets (groups 9 and 10), microbrush (groups 11 and 12), absorbent paper (groups 13 and 14). The last group was not dried; the dentin surfaces were left overwet (groups 5 and 6). Prime & Bond 2.1 adhesive was applied on the odd-numbered groups and Scotchbond Multi Purpose on the even-numbered groups. Z100 composite cylinders were bonded to the adhesive and the specimens were subjected to a shear bond test. RESULTS: The Least-Squares Means test was used to compare the following results, where different letters indicate significantly different mean values: Group 9 (G9) = 23.2 MPa (a), G3 = 21.3 MPa (ab), G2 = 19.5 MPa (bc), G10 = 18.6 MPa (bc), G14 = 16.3 MPa (cd), G8 = 16.1 MPa (cd), G4 = 14.6 MPa (de), G13 = 14.0 MPa (de), G11 = 13.9 MPa (de), G7 = 13.5 MPa (de), G12 = 12.1 MPa (e), G1 = 8.2 MPa (f), G5 = 2.7 MPa (g), G6 = 2.4 MPa (g). CONCLUSION: The adhesion values were affected both by the degree of dentin wetness and by the adhesive systems.
Assuntos
Colagem Dentária/métodos , Dentina/química , Dessecação/métodos , Acetona , Análise de Variância , Resinas Compostas , Adesivos Dentinários , Humanos , Análise dos Mínimos Quadrados , Teste de Materiais , Dente Serotino , Ácidos Polimetacrílicos , Cimentos de Resina , Dióxido de Silício , Resistência à Tração , Água , ZircônioRESUMO
This study measured the gap that resulted from polymerization shrinkage of seven restorative resin composites after curing by three different methods. Contraction behavior, according to the specimen region, was also characterized. The materials used for this study were Alert (Jeneric/Pentron, Wallingford, CT 06492, USA), Surefil (Dentsply Caulk, Milford, DE 19963, USA), P60 (3M Dental Products, St Paul, MN 55144, USA), Z250 (3M), Z100 (3M), Definite (Degussa-Hüls, Hanau, Germany) and Flow-it (Jeneric/Pentron). The composite was placed in a circular brass mold 7 mm in diameter and 2 mm in height. Photo-activation was performed by a) continuous light (500 mW/cm2) for 40 seconds; b) stepped light with low intensity (150 mW/cm2) for 10 seconds and high intensity (500 mW/cm2) for 30 seconds and c) intermittent light (450 mW/cm2) for 60 seconds. The top and bottom surfaces were then polished and after 24 +/- 1 hours, the contraction gap was measured by SEM at variable pressure (LEO 435 VP, Cambridge, England). Results were analyzed by ANOVA and the means compared by Tukey's test (5%). The results demonstrated 1) the continuous light method presented the greatest gap values (15.88 microm), while the other methods demonstrated lower polymerization shrinkage values (stepped light, 13.26 microm; intermittent light, 12.79 microm); 2) restorative composites shrunk more at the bottom surface (15.84 microm) than at the top surface (12.11 microm) and (3) the composites Alert (12.02 microm), Surefil (11.86 microm), Z250 (10.81 microm) and P60 (10.17 microm) presented the least contraction gaps, followed by Z100 (15.84 microm) and Definite (14.06 microm) and finally Flow-it (23.09 microm) low viscosity composite, which had the greatest mean value.
Assuntos
Resinas Compostas/química , Restauração Dentária Permanente , Dióxido de Silício , Zircônio , Análise de Variância , Resinas Compostas/efeitos da radiação , Polimento Dentário , Humanos , Luz , Teste de Materiais , Microscopia Eletrônica de Varredura , Polímeros/química , Polímeros/efeitos da radiação , Siloxanas/química , Estatística como Assunto , Propriedades de Superfície , Terpenos/química , Fatores de Tempo , ViscosidadeRESUMO
This study quantified the light intensity transmitted by the reflecting wedges perpendicularly to the growth axis. The results demonstrated that the cervical wedges did reflect the light of 180 degrees and original light intensity diminished by 83.9%. The maximal light intensity transmitted to the resin by the wedge was less than 8% of that receiving direct exposure to the curing wand. Differential measurements made on points closely spaced along the sides of the wedge indicated a maximal intensity at approximately 2 mm from the base of the wedge.
Assuntos
Resinas Compostas/química , Infiltração Dentária/prevenção & controle , Luz , Modelos Lineares , Dente Molar , Óptica e Fotônica , EspectrofotometriaRESUMO
PURPOSE: To compare the resin bond strength using different methods to remove the excess water from the dentin while maintaining it moist. MATERIALS AND METHODS: 60 human molars were randomly divided into four treatment groups of 15 teeth each as follows: Group 1: A wet bonding technique was used as recommended by the manufacturer and was used as a control group. The exposed occlusal dentin surfaces were conditioned with 32% phosphoric acid (Uni-Etch) for 15 seconds and rinsed for 15 seconds. 40 microL of distilled water was added to standardize the content of the water on dentin surface. The conditioned dentin surfaces were gently blow-dried for 3 seconds with oil-free compressed air. The tip of the syringe was placed at 2 cm from the dentin surface. One coat of the One-Step primer/adhesive was applied to the dentin surface using a fully saturated brush tip, allowed to remain on the surface undisturbed for 3 seconds, and then gently air-dried for 3 seconds from a distance of 1 cm to remove excess solvent and water. A second coat of the primer/adhesive was applied and gently air-dried from a distance of 1 cm. The primer/adhesive was light-cured for 10 seconds. Resin composite (Z100, shade A3) was then polymerized for 40 seconds. Group 2: The dentin surface was blot-dried by applying tissue paper (Kimwipes EX-L) adjacent to the exposed area; Group 3: The excess water on the dentin surface was removed using an applicator brush (Bend-a-Brush) for 5 seconds; Group 4: A small dry hydrophilic cotton pellet was gently applied over the dentin surface to remove the excess water. The sequential steps for these three groups were similar to those of Group 1. The dentin surface remained visibly moist in all procedures. After light-curing, the specimens were thermocycled (5 degrees and 55 degrees C, 500 cycles, 30-second dwell time). The specimens were sheared and the data were analyzed using ANOVA and Tukey's test methods. The site of failure was analyzed using a stereomicroscope and a scanning electron microscope. RESULTS: ANOVA revealed that there was a statistically significant difference between the groups (P < 0.05). Turkey's test revealed that Group 1 was significantly lower than Groups 2, 3 and 4 with no difference between the last three groups (P < 0.05). All samples showed resin cohesive failures.
Assuntos
Resinas Compostas/química , Colagem Dentária/métodos , Adesivos Dentinários/química , Dentina/efeitos dos fármacos , Análise de Variância , Colagem Dentária/estatística & dados numéricos , Dentina/ultraestrutura , Humanos , Técnicas In Vitro , Microscopia Eletrônica de Varredura , Dente Molar , Distribuição Aleatória , Camada de Esfregaço , Propriedades de Superfície , Resistência à Tração , Fatores de Tempo , ÁguaRESUMO
The flexural deflections of human dentin, Herculite XR, Dycal, Vidrion F, zinc phosphate base, and combinations of composite-base were determined. The influence of the flexural deflections in the marginal microleakage was also determined for the composite-base combinations. The flexural deflection test for dentin showed no statistically significant differences between the two floor cavity depths studied. There were significant differences among cements when the thickness of the base was 1 mm whereas no differences occurred at 2 mm. The composite-base combinations did not present statistical differences. There were no statistically significant differences in the microleakage levels among loaded and non-loaded specimens; however, dye penetration was visually greater in loaded samples.
Assuntos
Resinas Compostas/química , Forramento da Cavidade Dentária , Infiltração Dentária , Adaptação Marginal Dentária , Dentina/química , Cimentos de Resina , Hidróxido de Cálcio/química , Fenômenos Químicos , Físico-Química , Cimentos de Ionômeros de Vidro/química , Humanos , Teste de Materiais , Minerais/química , Maleabilidade , Cimento de Fosfato de Zinco/químicaRESUMO
PURPOSE: To evaluate the influence of protective agents (varnish and glaze-resin resin) on water solubility of two glass ionomer restorative cements (Chelon-Fil and Vidrion-R), with the graviometrical test (A.D.A Specification No 9). MATERIALS AND METHODS: Fifteen samples of each restorative cement were obtained and divided in one control and two experimental groups: (a) control, no protection; (b) protected with varnish; (c) protected with glaze-resin. On the two experimental groups, after the initial gelification reaction, the specimens were protected and immersed in distilled water for the period of 1 and 24 hours. RESULTS: The two glass ionomer restorative cements tested required surface protection to avoid the early solubility. Among the protective materials evaluated, the varnish was the most effective agent.
Assuntos
Restauração Dentária Permanente/métodos , Cimentos de Ionômeros de Vidro/química , Cimentos de Resina , Análise de Variância , Forramento da Cavidade Dentária , Materiais Dentários , Adesivos Dentinários , Laca , Compostos Orgânicos , Solubilidade , Propriedades de Superfície , Água/químicaRESUMO
The influence of fluoride solutions on the surface roughness of polished and nonpolished composites with Sof-Lex discs was verified. Concise and Herculite XR samples were exposed to the action of 1.23% acidulated phosphate fluoride rinse, 1.23% acidulated phosphate fluoride gel, and 0.2% neutral phosphate fluoride rinse for 4 min each. The average roughness values obtained by perfilometer showed that all fluoride solutions produced surface alterations in the samples. In the unpolished samples, more roughness was produced in Concise etched by 1.23% acidulated phosphate fluoride rinse. In the polished samples, the 1.23% acidulated phosphate fluoride gel produced greater alterations in Herculite XR, and the neutral rinse in Concise samples.
Assuntos
Fluoreto de Fosfato Acidulado/química , Bis-Fenol A-Glicidil Metacrilato/química , Resinas Compostas/química , Fluoretos Tópicos/química , Cimentos de Resina , Teste de Materiais , Microscopia Eletrônica de Varredura , Propriedades de SuperfícieRESUMO
This in vitro study evaluates the effect of storage time and acid etching on the tensile bond strength of glass ionomer cement to composite resins. The bonded assemblies were stored at 100% relative humidity and 37 degrees C for 1 hour, 1 day, 1 week, 1 month and 3 months. The test specimen was loaded at tension to failure on an Otto Wolpert-Werke testing instrument with a crosshead speed of 6 mm/min. The results showed a significant statistical difference for etched Vidrion F when compared to etched Ketac Bond at all storage periods. The unetched samples were statistically similar at 3 months, with the highest values for Vidrion F.
Assuntos
Resinas Compostas/química , Colagem Dentária , Cimentos de Ionômeros de Vidro/química , Condicionamento Ácido do Dente , Teste de Materiais , Resistência à Tração , Fatores de TempoRESUMO
The use of disinfectants on the dentin surface contributes to superficial cleaning and removal of remaining microorganisms of the carious process. However, the effect of these agents on the adhesion of resin materials to the dentin surface of primary teeth has not been established. This study evaluated the dentin micromorphological effects due to the use of antimicrobial agents in the different depths of dentin. Twenty-five buccal surfaces of primary molars were prepared from the sectioned teeth, ground flat and polished with silicon carbide paper of different grits. The surfaces were treated with 32% phosphoric acid with benzalkonium chloride (Bisco), 35% phosphoric acid gel (3 M), 3% benzalkonium chloride solution by itself or 10% maleic acid. All agents were applied for 15 seconds on the dentin surface. The samples were washed with distilled water, dried and coated with gold for observation of the dentin surface with the scanning electron microscope. The samples were subdivided according to the dentin depth in upper, middle and lower areas. The following was observed: presence of smear layer, opening of the dentin tubules, and inter and intratubular dentin morphology. The effects of the antimicrobial agents were compared in the different depths of the dentin. The results demonstrated that the surface conditioned with 3% benzalkonium chloride solution presented few disclosed dentin tubules. The use of the 32% phosphoric acid with benzalkonium chloride completely removed the smear layer and increased the diameter of the dentin tubule openings. The 35% phosphoric acid totally exposed the tubules in the upper area of the analyzed surface but partially exposed them in the middle and lower areas. The 10% maleic acid totally removed the smear layer, left all the tubules opened and conditioned the intertubular dentin. It was concluded that in the different depths of the dentin surface, conditioning with 10% maleic acid in primary teeth showed the most consistent micromorphological characteristics compared to the other agents used in this study.
Assuntos
Anti-Infecciosos Locais/farmacologia , Dentina/efeitos dos fármacos , Dente Decíduo/efeitos dos fármacos , Condicionamento Ácido do Dente , Anti-Infecciosos Locais/administração & dosagem , Compostos de Benzalcônio/administração & dosagem , Compostos de Benzalcônio/farmacologia , Compostos Inorgânicos de Carbono , Criança , Colagem Dentária , Polimento Dentário , Dentina/ultraestrutura , Humanos , Maleatos/administração & dosagem , Maleatos/farmacologia , Microscopia Eletrônica de Varredura , Microtomia , Ácidos Fosfóricos/administração & dosagem , Ácidos Fosfóricos/farmacologia , Resinas Sintéticas/química , Compostos de Silício , Camada de Esfregaço , Tensoativos , Dente Decíduo/ultraestruturaRESUMO
This 30-day study, compared the amounts and patterns of fluoride release from 5 commercially available fluoride-containing pit and fissure sealants: FluroShield, Helioseal-F, Ultraseal XT, Baritone L3, and Teethmate-F; Delton without fluoride, was used as control. Disc-shaped samples of each sealant were immersed in distilled water and the fluoride release was measured periodically until day 30. All the fluoridated sealants tested released measurable fluoride throughout the test period in a similar pattern: the greatest amount of fluoride was released in the first 24 hours after mixing, fell sharply on the second day and decreased slowly for the last days. On day one, Baritone L3 released significantly more fluoride than all other materials. Teethmate-F released the highest amount of fluoride during all the other time intervals from day 2, until day 30.